The reason why Zhao Hai released the undead creatures was to see how strong they were when they were using guns. At the same time, he didn't want to let the flame weavers escape. If they did, the Army would know and it would be even more troublesome.
Fortunately, those undead creatures didn't disappoint him. When they lined up and fired, their power was still great. Zhu Huo and his demon beasts were killed without any ability to fight back.
Zhao Hai was quite satisfied with the results. Although the guns would be more effective if they were given to a stronger person, the battle had fully demonstrated that the guns improved by the space were quite powerful.
Zhao Hai had 100000 soldiers, while the enemy only had 2000. They had already killed nearly 1000 enemies with cannons. If Zhao Hai and the others charged forward, the flame weaving tribe wouldn't be able to hold on.